I dropped the drain pan from the tranny, and it was an easy fix to replace the “Governor Pressure Sensor”.
Test drove the truck and I had all the gears back and the shift ranges were smooth and at the appropriate speeds.
It took longer to clean up all the tranny fluid that I spilled on the floor than it took to replace the sensor.
I was doing great until the pan slipped out of my hand.
Yosemite